one idea may be to change the way the government measures inflation. that may sound like a small change, but, as darren gersh reports, it could have a big impact. >> reporter: if the price of oranges goes up, consumers will buy apples and other cheaper foods. we know that. economists call that switching "substitution," but that change in behavior doesn't show up in the official inflation rate. so most economists think the current consumer price index overstates the actual cost of living. that's important because the inflation rate is used to set tax brackets and social security benefits. moving to a more accurate inflation measure called the "chained c.p.i." would cut the deficit by $200 billion over ten years. supporters say the change wouldn't cut benefits. >> if we're making the change to reflect what is the real cost of living, as opposed to a different one, then you are not reducing them; you're just truing up what you should be getting. not something that-- i hate to use the term-- that might be inflated beyond what it should have been. >> report